Exploring the hormetic effects of radiation on the life table parameters of Spodoptera frugiperda.

BACKGROUND: Spodoptera frugiperda, a global agricultural pest, can be effectively controlled through the sterile insect technique. However, exposure to low-dose radiation below the sterilization threshold may induce hormetic effects. Here, the biphasic aspects of the fertile progeny population of S. frugiperda were analyzed using an age-stage, two-sex life table after dosing male and female pupae with 10-350 Gy gamma radiation. RESULTS: The parental sterilizing dose for 6-day-old female and male pupae was 200 and 350 Gy, respectively. The total longevity, pre-adult survival rate, net reproduction rate, and intrinsic growth rate of the offspring population increased with decreasing radiation doses from 250 to 10 Gy. Offspring population of parents treated with low doses of 10-100 Gy showed better life table parameters compared to non-irradiated controls. Females and males fecundity irradiated with 10, 50, and 100 Gy and 10 Gy, respectively, exceeded controls, producing 2339.4, 2726.4, 2311, and 2369 eggs, as opposed to 1802.9 eggs produced by the controls. Males irradiated with 10 Gy displayed the highest intrinsic rates of increase and net reproduction rate, at 0.1709 and 682.3, respectively. Projections from the survival rate and fecundity indicated that female and male S. frugiperda populations after 10 Gy irradiation may grow considerably faster than the controls. CONCLUSION: This study explores the hormetic effects of low-dose radiation on S. frugiperda through life table analysis, while providing enhancements for utilizing substerilizing gamma dose in a modified F1 sterility technique. © 2023 Society of Chemical Industry.

[Rapid determination of five halobenzoquinones in aquatic products by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry].

Halobenzoquinones (HBQs), which are emerging chlorinated disinfection byproducts (DBPs), have attracted increasing attention because they are frequently detected in treated tap water, entrainment water, etc. These compounds are mainly generated during the water treatment process using chlorine, chloramine, and chlorine dioxide as disinfectants, and display more toxic effects than regulated DBPs, such as trihalomethane and haloacetic acid. HBQs have been recognized as potential bladder carcinogens and are harmful to the nervous system. Additionally, they can exert genotoxic effects and cause oxidative damage to DNA and proteins. The risk of HBQs in aquatic products is expected to rise because the disinfection of public facilities has significantly increased in recent years. Therefore, developing a sensitive and accurate analytical method to detect HBQs in aquatic products is of great importance. Several analytical methods, including gas chromatography, gas chromatography-mass spectrometry, electrochemical methods, liquid chromatography, and liquid chromatography-tandem mass spectrometry, can be used to identify and quantify HBQs in water. However, to the best of our knowledge, no reports on the determination of HBQ levels in aquatic products are yet available. Further, pretreatment is essential for HBQ determination because of the complex matrix effects of aquatic products. Herein, a sensitive and accurate method based on the QuEChERS technique coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of five HBQs in aquatic products. For the QuEChERS procedure, the pretreatment conditions, such as the extraction solvent and adsorbent species, were systematically optimized. The sample was extracted with 10 mL of 10% methanol acetonitrile solution (containing 0.1% formic acid), dehydrated, and centrifuged with sodium chloride and anhydrous magnesium sulfate. The supernatant was purified using a QuEChERS packing material consisting of 50 mg N-propylethylenediamine (PSA), 30 mg of graphitized carbon black (GCB), and 30 mg of neutral alumina (Al2O3), dried with nitrogen, and concentrated. The five HBQs were separated on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm) using 0.25% acetonitrile formate solution and 0.25% formic acid aqueous solution as the mobile phase under a gradient elution program and then detected using UPLC-MS/MS with negative electrospray ionization (ESI-) under multiple reaction monitoring (MRM) mode. Quantitative analysis was performed using a matrix-matched external standard method. The five HBQs achieved rapid separation within 6 min, indicating that the proposed method has a much shorter separation time compared with previous studies. The matrix effect was evaluated by establishing a matrix-matched calibration curve. The results showed that 2,5-dichloro-1,4-benzoquinone (2,5-DCBQ) presented a matrix-enhancing effect, whereas the other HBQs displayed matrix-inhibiting effects. In particular, tetrachlorobenzoquinone (TCBQ) exhibited strong inhibitory effects. Under the optimized experimental conditions, the five HBQs demonstrated good linear relationships in the range of 1.0-50.0 µg/L, with correlation coefficients (r)≥0.9992. The detection limits of the method were 0.15-0.8 µg/kg, and the recoveries of the target compounds were 85.9%-116.5%. The relative standard deviations were 1.4%-8.2%, which indicates good reproducibility. The proposed method was successfully applied to actual sample detection, and 2,6-dichloro-3-methyl-1,4-benzoquinone (2,6-DCMBQ) was detected in grass carp. The proposed method is convenient, sensitive, accurate, and suitable for the simultaneous determination of five HBQs in aquatic products. Moreover, the developed method provides a reliable reference for the routine monitoring of trace HBQs in food samples.

Immobilization and enzymatic properties of glutamate decarboxylase from Enterococcus faecium by affinity adsorption on regenerated chitin.

Glutamate decarboxylase (GAD, EC 4.1.1.15) is an important enzyme in gamma-aminobutyric acid biosynthesis and DL-glutamic acid resolution. In this study, the Enterococcus faecium-derived GAD was successfully immobilized by regenerated chitin (RC) via specific adsorption of cellulose-binding domain (CBD). The optimal binding buffer was 20 mmol/L phosphate buffer saline (pH 8.0), and the RC binding capacity was 1.77 ± 0.11 mgcbd-gad/grc under this condition. The ratio of wet RC and crude enzyme solution used for immobilization was recommended to 3:50 (g/mL). To evaluate the effect of RC immobilization on GAD, properties of the immobilize GAD (RC-CBD-GAD) were investigated. Results indicated RC-CBD-GAD was relatively stable at pH 4.4-5.6 and temperature - 20-40 °C, and the optimal reaction pH value and temperature were pH 4.8 and 50 °C, respectively. When it was reacted with 5 mmol/L of follow chemical reagents respectively, the activity of RC-CBD-GAD was hardly affected by EDTA, KCl, and NaCl, and significantly inactivated by AgNO3, MnSO4, MgSO4, CuSO4, ZnSO4, FeCl2, FeCl3, AlCl3, CaCl2, and Pb(CH3COO)2. The apparent Km and Vmax were 28.35 mmol/L and 147.06 µmol/(gRC-CBD-GAD·min), respectively. The optimum time for a batch of catalytic reaction without exogenous pH control was 2 h. Under this reaction time, RC-CBD-GAD had a good reusability with a half-life of 23 cycles, indicating that it was very attractive for GABA industry. As a novel, efficient, and green CBD binding carrier, RC provides an alternative way to protein immobilization.

Enhancing effect of macroporous adsorption resin on gamma-aminobutyric acid production by Enterococcus faecium in whole-cell biotransformation system.

Gamma-aminobutyric acid (GABA) biosynthesis depended to a great extent on the biotransformation characterization of glutamate decarboxylase (GAD) and process conditions. In this paper, the enhancing effect of D101 macroporous adsorption resin (MAR) on the GABA production was investigated based on the whole-cell biotransformation characterization of Enterococcus faecium and adsorption characteristics of D101 MAR. The results indicated that the optimal pH for reaction activity of whole-cell GAD and pure GAD was 4.4 and 5.0, respectively, and the pH range retained at least 50% of GAD activity was from 4.8 to 5.6 and 4.0-4.8, respectively. No substrate inhibition effect was observed on both pure GAD and whole-cell GAD, and the maximum activity could be obtained when the initial L-glutamic acid (L-Glu) concentration exceeded 57.6 mmol/L and 96.0 mmol/L, respectively. Besides, GABA could significantly inhibit the activity of whole-cell GAD rather than pure GAD. When the initial GABA concentration of the reaction solution remained 100 mmol/L, 33.51 ± 9.11% of the whole-cell GAD activity was inhibited. D101 MAR exhibited excellent properties in stabilizing the pH of the conversion reaction system, supplementing free L-Glu and removing excess GABA. Comparison of the biotransformation only in acetate buffer, the GABA production, with 50 g/100 mL of D101 MAR, was significantly increased by 138.71 ± 5.73%. D101 MAR with pre-adsorbed L-Glu could significantly enhance the production of GABA by gradual replenishment of free L-Glu, removing GABA and maintaining the pH of the reaction system, which would eventually make the GABA production more economical and eco-friendly.

[Label-Free Resonance Light Scattering Detection of Hg²âº Based on Specific Structure Thymine-Hg²âº-Thymine].

A new label-free resonance light scattering method for the highly selective and sensitive detection of mercury ion was designed. This strategy makes use of the target-induced DNA conformational change to enhance the resonance light scattering intensity leading to an amplified optical signal. The Hg²âº ion, which possesses a unique property to bind specifically to two DNA thymine (T) bases, in the presence of Hg²âº, the specific oligonucleotide probes form a conformational reorganization of the oligonucleotide probes from single-chain structure to duplex-like complexes, which can greatly enhance the resonance light scattering intensity. Under the optimum experimental conditions, the enhanced resonance light scattering intensity at 566 nm was in proportion of mercury ion concentration in the range 7.2 x 10⁻9 x 10⁻8 mol · L⁻¹ with the linear regression equation was ΔI = 5.12c+3.55 (r = 0.999 5). This method was successfully applied to detection of Hg²âº in enviro nmental water samples, the RSD were less than 1.9% and recoveries were 99.4%-104.3%. This label-free strategy uses the mercury specific oligonucleotide probes as recognition elements and control the strength of resonance light scattering by changing the concentration of Hg²âº. It translating the small molecule detection into the DNA hybridization behavior leading to an amplified resonance light scattering signal can well enhance the sensitive detection of Hg²âº. With amplification by DNA hybridization behavior, the sensitivity for the detection of Hg²âº can achieve 2.16 x 10⁻9 mol · L(⁻¹). In this study, the stacked T-Hg²âº-Tfunctioned not only as amplification property but also as an selective recognition. The highly specific detection of Hg²âº is attributed to the formation of a stable T-Hg²âº-T complex.

[Causes of death of advanced schistosomiasis patients in Huacao Town, Shanghai].

OBJECTIVE: To explore the causes of death of advanced schistosomiasis patients in Huacao Town, Shanghai, so as to improve the relief measures for advanced schistosomiasis patients. METHODS: The data of advanced schistosomiasis patients from 2007 to 2012 were collected and analyzed statistically. RESULTS: There were totally 340 advanced schistosomiasis patients, and among them there were 110 deaths and 230 survival cases currently. The deaths of the men were less than those of the female with the gender ratio of 1: 1.08. The average age of deaths of advanced schistosomiasis patients was 77.98 years, while the patients with age older than 70 years accounted for 90.00%. There were 36 advanced schistosomiasis patients died of cancer, accounted for 32.73%, and 34 deaths died of schistosomiasis, accounted for 30.91%. CONCLUSION: The mortality rate of advanced schistosomiasis patients shows a rising trend in Huacao Town, and they mainly die of cancer and schistosomiasis.

[Secular changes on the morphological development and nutrition status of Tibetan students from 1985 to 2005].

OBJECTIVE: To study the secular changes on both morphological development and nutritional status among Tibetan students, from 1985 to 2005. METHODS: Data from the Chinese national survey on students' physical fitness and health in 1985, 1995, 2000 and 2005 were used to analyze and find out the difference of the morphological development and nutrition status of Tibetan students aged 7 - 18 years in different years. RESULTS: From 1985 to 2005, the height and weight of Tibetan students had a growing trend. The height and weight of schoolboys and schoolgirls aged 7 - 18 years increased 3.94 cm, 5.08 kg, 2.25 cm, and 4.24 kg respectively, while the circumference decreased without significance. The prevalence rates of underweight and malnutrition in Tibetan students further went down along with the improvement of their nutritional status. However, the prevalence rates on both overweight and obesity increased continuously, affecting the health status of Tibetan students. CONCLUSION: From 1985 to 2005, the morphological development of Tibetan students had a growing trend and their nutrition status improved. However, the prevalence of overweight and obesity continuously increased.